Variable liquid resistance apparatus



June 10, 1952 N. R. BENCHEMOUL VARIABLE LIQUID RESISTANCE APPARATUS 4 Sheets-Sheet 1 Filed Sept. 22, 1950 WIN.

W F. N H c V N NF. 5 ON l 0n E nu 2 0 N IA W June 10, 1-952 BENCHEMOUL 2,599,806

VARIABLE LIQUID RESISTANCE APPARATUS Filed Sept. 22, 1950 v 4 Sheets-Sheet 2 INVENTOR NORBERT R. BENCHEMOUL June 10, 1952 N. R. BENCHEMOUL 2,599,806

VARIABLE LIQUID RESISTANCE APPARATUS Filed Sept. 22, 1950 4 Sheets-Sheet 3 INVENTOR NORBE RT R. BENCHE MOUL J 1952 N. R. BENCHEMOUL VARIABLE LIQUID RESISTANCE APPARATUS 4 Sheets-Sheet 4 Filed Sept'i 22, 1950 IIIII'UIIIIIIIIIIIIII INVENTOR NORBERT R. BENCHEMOUL Patented June 10, 1952 UNITED STATES FATENT OFFICE Application September 22, 1950, SerialNo. 186,252 .In France September 29, 1949 4 Claims. (Cl. 201-57) .Ihepresent invention concerns an apparatus comprising, within an enclosure full of liquid, at least two immersed electrodes having parallel surfaces and liable to be relatively displaced parallelly to one another, so that the surfaces of these electrodes opposite one another can be varied, without varying their distance apart. As a result the liquid resistance between these electrodes varies accordingly.

.In a preferred embodiment, the electrodes are constituted by coaxial revolution surfaces and are rotatable relatively to one another about their common axis.

Such an apparatus can be used either as a source of heat owing to the calories evolved in the liquid by Joules effect, or as a mere rheostat, for instance as starting rheostat or regulating rheostat.

Whatever be the applications of this apparatus, it may be of advantage, for the purpose of evacuating the calories evolved, to circulate the liquid either along a closed circuit, for instance through a radiator, or along an open circuit in which case the apparatus operates as the essential element of a heating cock.

In order to increase the operative surfaces of the electrodes without unduly increasing the size of the enclosure containing the liquid, it is convenient to imbricate the electrodes, so that both sides of any one electrode can be brought opposite the corresponding sides of the other electrode. The active portions of the electrodes are thus arranged in staggered formation.

The apparatus of the invention is particularly convenient in the case of alternating currents as they do not practically cause electrolysis.

In the case of single-phase current, the apparatus can merely comprise two electrodes one of which is movable, the other being preferably stationary.

In the case of multiphase current, it is possible to use a number of sing1e-phase apparatus equal to the number of phases, to connect them across the phases or between the phases and a neutral point, and to link mechanically these apparatus in such a way that the relative positionS of the electrodes of all the apparatus be the same at thesame time.

It is also possible to resort to a star-coupling by using-a number of stationary electrodes equal to the'number of phases, these electrodes being regularly distributed about the axis of the enclosure, and an equal number of movable electrodes electrically and mechanically connected to each other, these latter electrodes being also regularly distributed about said axis.

In this latter case, each electrode which conveniently assumes the shape of a cylindricalportion, extends over an arc of 11/11 (n being the number of phases) and the stationary electrodes as Well as the movable ones are separated by angular intervals of w/n.

Other objects and advantages of the invention Will be aparent during the course of the following description. In the accompanying drawing forming a part of this application and in which like numerals are employed to designate like parts throughout the same,

Fig. l is a vertical section through a singlephase apparatus, taken along line II of Fig. 2,

Fig. 2 is a bottom plan view, the adjusting knob being removed for clearness sake,

Fig. 3 is a top plan view of the apparatus,

Fig. 4 illustrates the apparatus fitted up on a cook, the latter being shown in vertical section,

Fig. 5 is a perspective view of a three-phase rheostat according to the invention,

- Figs. 6 and 7 are plan views showing the connecting system and the adjusting system of this rheostat,

Fig. 8 is a diagram showing th electrical and mechanical connections of the stationary electrodes and of the movable ones, and

Fig. 9 is a perspective view with diametrical section of the rheostat of Figs. 5 to 8.

As shown in Figs. 1, 2 and 3, the single-phase apparatus comprises a cylindrical casing I made of insulating and liquid-tight material, open at one end la, and whose bottom lb has a central hole 2 around which a circular groove 3 is'provided. This central hole 2 extends downwards (on Fig. 1) through a semi-cylindrical shoulder 4.

The central hole 2 contains a conducting sleeve 5 the lower part of which is hollow and engages a knob 6 of insulating material. Half of the outer surface of this part 5a is covered byth'e shoulder 4, the other half (located towards the left-hand side of Fig. 1) being uncovered. A semi-cylindrical conducting strip 1 is applied on this free half of 511, by means of a pusher 8 (Fig. 2) urged by a spring (not shown) lying inside a cylinder 9 secured to the casing l. The strip 1 is connected to a terminal in screwed into the bottom lb of the casing and provided with a tightening nut l I.

On the upper surface of the bottom lb and of the sleeve 5, there is provided a shaped tightness joint [2 held in position by a ring I3 having a circular rib Ilia fitting the groove 3. The circular flange l5 of a semi-cylindrical metal plate I6 is applied, through a washer I4, on this ring IS. The sleeve 5, the ring l3, the washer l4 and the flange [5 are all secured to the knob 6 by means of a stainless metal screw IT.

The upper edge (Fig. 1) of plate It is turned over and secured, for instance by welding, to the edge also turned over of a further semi-cylindrical metal plate arranged coaxially to and opposite the former one.

Between these two plates [6 and I8, another semi-cylindrical coaxial plate I9 is inserted; its lower edge I900 is turned over and applied on the turned over lower edge 20a of a further semicylindrical coaxial plate 20. Hence the two pairs of plates, l6 and 18 on the one hand, 19 and 23 on the other hand, are arranged in staggered formation and coaxially to each other and to the casing I.

Plates l9-20 are secured, by means of a screw 2 I, to a metal terminal 22 extending right through the bottom lb of the casing and provided with a protruding threaded rod 23 carrying a nut 24 tightened upon a washer 25.

The part of the apparatus above the knob t is wrapped in a metal sheathing 25 which can be enamelled and used as embellisher.

The apparatus operates as follows:

The terminals I and 22 are connected to a source of current, for instance the mains, and the plates Iii-48 and I920 are thus energized. As the casing 1 contains a conducting liquid, water for example, the plates Iii-l8 and Ill-20 constitute electrodes connected by the liquid mass lying therebetween. The electrode l6--l8 being fast with knob 6, its position in casing I, is adjustable. Whatever be its position, electrode |8--l8 is always live owing to the permanent contact between strip 1 applied by pusher 8 on the metal surface a of sleeve 5 which acts as a collector-ring. It is to be noted that no current flows through the resilient pusher 8 which merely plays a mechanical part. It is thus less liable to get damaged than if it were used as a terminal for the purpose of avoiding strip 1.

It is to be further noted that the tightening nuts H and 24 of the terminals, as well as the collector-ring 5a are located in a liquid-tight compartment between the bottom lb of the casing and the knob 6, thus avoiding any danger of electric leakages and of undue heating.

As known, the value of liquid resistance is proportional to the surfaces facing one another, of the electrodes dipping into this liquid, and inversely proportional to the distance between these electrodes. It is obvious that, in the case of the above apparatus, the value of the liquid resistance will depend on the relative position of the electrodes l6l8 and 19-20. In particular, it will vary, in a continuous way, from a minimum value corresponding to the position for which the electrodes are completely engaged into one another, to a maximum Value corresponding to the position for which the electrodes are diametrically opposite. Thus the thermal output of the apparatus varies between two predetermined limits.

In an embodiment of the invention (Fig. 4),

this apparatus is fitted up on a cock adapted to this purpose. The water inlet a is controlled by a gate-valve b actuated as usual by means of a knob g. The water flows, through a duct 0, into the central portion of the apparatus. This water, after having been heated, flows out through the conduit (1 whose diameter is smaller than that of duct 0, and through the anti-splash nozzle e. Of

course, the feed-current of the apparatus must be switched oil as soon as the tap is turned off. Nevertheless, in case of absentmindedness, most of the water remaining inside the apparatus is expelled by air stored up at its upper part and the remainder being still heated is evaporated, the steam issuing through conduit d and nozzle 6. When this remainder has evaporated, the current is automatically cut oil.

The body-portion f of the cock shown in the drawing is conveniently made of insulating material and the nozzle 6 is internally lined with an insulating layer of enamel. This results in an important drop in voltage due to the length of the water columns flowing into and out of the apparatus. Indeed the water flowing into and out of the apparatus follows relatively long paths along ducts a-c and conduits rZ-e respectively. Thus, if slight current leakages occur because of an insulation or a contact defect, a complementary safety is ensured by the voltage drop along these water columns, thus avoiding even a slight danger of electrocution.

In the example of Fig. 4, the axis of the appa ratus is horizontal, the stationary electrode lying in the lower half of the casing. This disposition is particularly convenient for it enables to keep the power consumption to a substantially constant value, whatever be the water output. It is known indeed that the resistivity of water varies inversely as its temperature. Besides, the temperature of water depends on its flowing speed, and more specifically on the time during which it is subjected to an electric current, i. e. on the time during which it flows between the electrodes. Hence when the tap is turned further on, the temperature of the water decreases and its resistivity rises; as a result the current tends to decrease. However, an increase in fiow corre sponds to an increase of the immersed surfaces of the electrodes since the water level rises in the casing (this is due to the fact that the diameter of the inlet duct c is greater than the diameter of the outlet conduit 11). Hence the resistance of water decreases and the current tends to increase. Practice shows that these two opposite tendencies substantially balance and the current remains constant.

If, on the other hand, it is aimed at achieving a uniform temperature independent of the flow, it is sufficient to link the gate-valve b to the movable electrode. This can be done through various known means (not shown) e. g. a geartrain between knob g and knob 6, or else a direct connection of knob g to the movable electrode thus doing without knob 6. The apparatus of the invention is particularly well adapted for such a purpose as its electrical adjustment is effected by rotating an electrode, the control of the flow being also effected by a rotary member.

Thus in increasing the flow of water, the movable electrode is simultaneously driven in the direction corresponding to a decrease in resistance and hence to an increase of absorbed power, so as to keep constant the temperature of water. In the caseof a decrease in flow, the opposite phenomenon occurs.

Obviously the above apparatus can have other applications than those described with reference to Fig. 4. It can be fitted up on a heating element or water radiator of any type, the water being circulated by means of a pump or merely by thermo-siphon.

Furthermore, the apparatus can be used, not as a heating element, but merely as a rheostat.

am havin been fllle.

. afieiitlyi circulatd -preferably- -elong a closed-circuit}through iiiooler.

"rl'ie-apiilic fs'tat id, not plicatl'ons :"li'quid.

"f Figsf fi to 9 show a r m-erarrapparatus' accordin to the inver'itipn whiehisusd'asa threephase 'rheost'at.

This rheostat which is shown .in perspective view in Figsfi 'and"9,"comprises"aninsulating cylind'r'icfal casing fl similarinc easing :or Fig. l.

Above this casing 21, there isi zprov'ided' a 't'anKiZB tightly sealed by aigplug 23. The -{liquid mass stored in this tank limits the rise in temperature of .the'fapparatus. Cooling fins 3.3 .are radially'secured to thistank. The'casing 21 carries a'tbaseflange f 31' provided with three terminals 3.2de- "signed to'be connected to 'a 'three-phasecircuit. A stationary circular 'plate"'33 of insulating inaterial and a further".circulari plate' 34 coaxial and rotatable relatively to the former one, are located underneaththe flange3l. 'Ihe latter plate 34 which is also made of insulating material is actuated by means of an arm 35 secured in 36 underneath it.

The plate 33 carries on its lower side, three studs 31 (Figs. 7, 8 and 9) electrically connected to the terminals 32. Each stud is integral with a resilient metal strip 38 shaped as an arc of circle of about 60; the three strips 38 separated by arcs of 60, are fitted up in a circular groove 39 on the surface of plate 33, so as to slightly protrude. Opposite each strip 38, a further strip 40 also shaped as an arc of circle concentric to and of same angular size as the former one, is located. These strips 40 are located in a circular groove 4| and connected, through bolts 42, to the three stationary and independent electrodes 43 which extend over sectors of 60 and are separated by intervals of the same value. The movable electrodes 46 integral with a common flange 60, have the same angular size as the stationary electrodes and are coaxial thereto. The flange 60 is secured to a shaft 44 which crosses the bottom of casing 21, the base-flange 3| and the plate 33. A shoulder of this shaft ensures tightness by cooperating with a washer 6|. This shaft ends at its lower part in a square portion 45 which fits the centre of plate 34.

The latter comprises, on its upper side (opposite that side of plate 33 shown in Fig. 7), three pistons 41 arranged at 120 to each other and connected together by a wire 48 embedded within the plate. These pistons 41 are urged by springs 62 (Fig. 9) and protrude above the surface of this plate 34. The latter further carries three contact brushes 49 (for instance curved strips), insulated from each other and arranged on the radii passing through the pistons 41.

The studs 31 of the plate 33 and the pistons 41 of the plate 34 are located on circumferences of the same radius. Furthermore the brushes 49 are so arranged and their size is such that they lie across the annulus formed by the grooves 394| of plate 33. i

In the position illustrated by Fig. 8, the brushes 49 not being in contact with the strips 3840, all the electrodes are out of circuit. A slight rotation of the plate 34 brings about this ations of the 'apparatus -as -a rheoifierinthei principle "m' the apcs thisisame apparatus tor-- yheating -a contaetthus' energizing these-ensues-awmenrra main live during the whole displacement 'ofthe -brushesi49 fr'om one end of strips- 38-40 to the other} the meva-ble star-coupled electrodes 1 43 "moving then from the positio'rfof--' Fig.- 3 (maximum resistance) to the position co -away for *v'ihi'chfthey-are entirely opposite the stationary electrodes:43-(minimum resistance). The pistons 4'!then'comeintocontactwith the studs 31 which I 'are therebyshortecircu-ited owing- -to*-the wire 48. The rotation of T plate 34 is limited-by' 'stops 50'5l- (Figf 7)' located onthe'- path of the-pistons 5&4 ofiand to the 'short-circuiting of the'rheostat. Thepslight current leakages occurring directly h'etween the stationary electrodes- 43 do not upset 'theQphaSe" equilibrium of the" circuit. It can be 1 shown that they are equivalentto three "large triangle-coupled resistors giving rise to equal and =-weal voltage drops. Furthermorethe heating of the liquid' is limited owing to thelarge cooling "surfacesof the tank 28' and'of the fins 30.

Obviously the above three phase apparatus-can l be used as aheating element similarly to' the ap- -paratusflesc'ribed with reference to Figs. 1 'to "4, justas the latter can be used as a single-phase rheo'stat.

The apparatus may be adapted to any multiphase supply circuit, by altering, in accordance with the number of phases, the number and. size of the various members. Thus for an n-phase circuit, the apparatus will comprise n pairs of electrodes, one electrode of each pairbeing stationary and the other one movable, all the movable electrodes being simultaneously displaced. These electrodes will be formed by cylindrical angular sectors of 1r/n separated by equal intervals. They may comprise a single surface (as in the example of Fig. 8) or several surfaces in staggered formation (as in the example of Figs. 1 and 9).

In the case of multiphase currents, it is of course possible to link mechanically several apparatus as that shown in Figs. 1 to 3, each of them being connected either across the phases or between a phase and a neutral point.

It is to be understood that the form of the in-- vention herewith shown and described is to be taken as a preferred example of the same and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

What I claim is:

1. In a variable liquid resistance apparatus, the combination of at least two electrodes constituted by coaxial portions of revolution surfaces, means for relatively rotating said electrodes about their common axis, at least one contact sector fast with and coaxial to one of said electrodes, and at least one contact member in sliding contact with said sector and fast with the other one of said electrodes.

2. In a variable liquid resistance apparatus, the combination of a pair of electrodes constituted by coaxial portions of revolution surfaces, means for rotating one electrode of said pair about its axis, a cylindrical contact sector fast with and coaxial to said latter mentioned electrode, an

0 electrical connection between said latter mentioned electrode and said sector, a resilient metal strip located around part of said cylindrical sector and fast with the other electrode of said pair, a resilient pusher member adapted to urge said strip into sliding contact with said cylindrical in positions corresponding to-the switching I sector, and a terminal electrically connected to said strip.

3. In a variable liquid resistance apparatus, the combination of a plurality of pairs of electrodes constituted by coaxial portions of revolu tion surfaces, means for simultaneously rotata plurality of terminals electrically connected to each one or the other sectors of said pairs of sectors.

4. In a variable liquid resistance apparatus,

the combination of a plurality of pairs of electrodes constituted by coaxial portions of revolution surfaces, means for simultaneously rotating one electrode of each of said pairs about their common axis, a pair of coaxial bridge-like contact sectors fast with and coaxial to each one of the other electrodes of said pairs of electrodes, a contact member in sliding contact with both sectors of each one of said pairs of sectors and fast with the former mentioned electrodes of said pairs of electrodes, means for electrically connecting one sector of each one of said pairs of sectors to each one of said other electrodes, a plurality of terminals electrically connected to each one of the other sectors of said pairs of sectors. said terminals being regularly arranged around the axis of said electrodes, and a stud fast with each one of said former mentioned electrodes. said studs being electrically connected to each other and being arranged regularly around the axis of said electrodes and at the same distance from this axis as said terminals.

NORBERT R. BENCHEMOUL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,241,567 Simmon et a1. Oct. 2, 1917 1,321,509 Colby Nov. 11, 1919 1,439,639 Pusey Dec. 19, 1922 1,550,16 l Heinrich Aug. 18, 1925 FOREIGN PATENTS Number Country Date 101,381 Australia July 1, 1937 

